ML19347C816

Ao:During Insp of Bergen-Paterson HSSA-10 Units on Steam Line B Isolation Condenser NE01B,hydraulic Shock & Sway Arrestors Found Devoid of Fluid.Cause Under Study.Units Will Be Replaced W/Units Rebuilt W/Ethylene Propylene Seal Matl

ML19347C816
Person / Time
Site:	Oyster Creek
Issue date:	11/13/1973
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8103040849
Download: ML19347C816 (3)

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Jersey Central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD e MORRISTOWN, N.J.07960

• 201-539-6111 General g , Public Utilities Corporation

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November 13, 1973 P - .

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Mr. A. Giambusso Deputy Director for Reactor Proj,ects j g

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Washington, D. C. 20545 9' O/

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Dear Mr. Giambusso:

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Subject:

Oyster Creek Station Docket No. 50-219 Hydraulic Shock and Sway Arrestor Failure This letter serves to report a failure of one (1) hydraulic shock and sway arrestor unit (HSSA) on the steam line for isolation condenser NE01B.

found while performing a monthly check of all units in the reactor building external to the drywell, as recommended by the Plant Operations Review Committee.

This event is considered to be an abnormal occurrence as defined in the Tech-nical Specifications, paragraphs 1.15B and D. Notification of this event, as required by the Technical Specifications, paragraph 6.6.2.a, was made to AEC Region I, Directorate of Regulatory Operations, by telephone on Saturday, November 3, 1973, and by telecopier on Monday, November 5, 1973.

While conducting an inspection of the hydraulic shock and sway arrestors (snubbers) located on various systems in the reactor building, but outside of the drywell, tne accumulator on one unit on the steam line to the "B" isolation condenser was found to be devoid of fluid.

Additionally, another unit on the steam line to the "A" isolation condenser was initially reported to be failed, but further inspection and eval-untion by the mechanical mair.tenance foreman and the maintenance engineer re-sulted in the unit being considered to be operable but low in accumulator fluid level.

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Upon disassembly and inspection of the accumulator installed on the ,

"B" isolation condenser, the spring loaded piston ring was found to be failed.

Although no deterioration or other unusual conditions could be visually determined,  ;

the U-cup on the accumulator piston head apparently was degraded to a point where it allowed the fluid to leak out. The unit had not been rebuilt during  ;

either the Spring 1973 Refueling / Turbine Generator Inspection nor during the l September 1973 Snubber / Turbine Control Valve Outage.

7/030 0$ $

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Mr. Giambusso November 13, 1973 Pertinent data is as follows:

Manufacturer: Bergen Paterson Pipe Support Company Type: HSSA-10 Serial No.: 469946 The initial inspection report indicated that one unit on the steam line for the "A" isolation condenser and one unit on the "B" isolation condenser were inoperable. Consequently, as. per the requirements of the Technical Specifi-cations, paragraph 3.8.D, an orderly plant shutdown was commenced upon notification of the situation. Meanwhile, an immediate reinspection was made on both snubbers with results as previously indicated. Nevertheless, preparations for an orderly shutdown continucd until the accumulator for the snubber on the "A" isolation condenser could be filled to a satisfactory level. This action was completed by 1845 Friday, November 2, 1973. The load drop which had been started was halted, and the plant returned to its previous operating level of 595 MWe(g). Follow-up action included replacement of the accumulator on the snubber installed on the "B" isolation condenser steam line, then replacement of the entire snubber unit on the "A" isolation condenser, steam line, since it had been leaking. This action was completed by 1910 Friday evening. A follow-up check was then made on Saturday evening to insure that no further fluid loss was occurring.

Amendment 67 to the FDSAR details the requirements for at least one isolation condenser to be available as a heat sink in the event of a loss of coolant accident. Both condensers would have been abic to perform this function; however, had an earthquake occurred which would have required proper functioning of all installed snubbers, the steam line to the "B" condenser may not have been '

able to withstand the anticipated forces. Consequently, should a rupture then have occurred, a release of reactor steam to the secondary containment would have resulted. Analysis of this accident has been made assuming a valve closure time of 60 seconds after the break, and found to be less severe than a rupture of the main steam line and subsequent closure of the main steam isolation valves. The significance of this event then is the increased probability of steam release to the secondary containment which, had that occurred with subsequent unit isolation, then would have resulted in a loss of redundancy of the isolation condensers to act as a heat sink.

In lieu of waiting an additional month to reinspect snubbers located in the reactor building, this reinspection will be conducted within the next two weeks. Based upon the inspection findings, a determination will be made as to an acceptable future inspection frequency.

In addition, four snubbers previously not included in the inspection program, two of which are located on the No. 2 containment spray system and two on the No. I core spray system, will be inspected promptly and will be in-cluded in subsequent inspections.

It is further intended that the ethylene propylene seal procurement l effort be continued such that any units rebuilt in the future would contain seals of this material.

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Mr. Gian6usso November 13, 1973 '

Enclosed ar.2 forty (40) copies of this report.

Very truly yours,

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/ ' / ) i Donald A. Ross I.

Manager, Nuclear Generating Stations DAR:cs l Enclosures ,

i cc: ' Mr. J. P. O'Reilly, Director i Directorate of Regulatory Operations, Region I f i

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